Go Down

Topic: Automatically varying POT values (Read 294 times) previous topic - next topic

harish017

Hey guys, I am using Schmitt Trigger for LFO ported to teensys input. Now, I want the lfo value to automate oscillators pitch in teensy. I thought of using I2C bus for this, between Schmitt Trigger and analog input of teensy mapped for pitch. I need to float assign wiper values that compare the varying LFO. Any thing in mind brothers?

Grumpy_Mike

#1
Aug 03, 2016, 04:55 pm Last Edit: Aug 03, 2016, 04:56 pm by Grumpy_Mike
Quote
Any thing in mind brothers?
Yes, what language are you speaking. It looks like English words but it makes no sense.

Quote
I am using Schmitt Trigger for LFO ported to teensys input
Schmitt Trigger - device to give a zero or one when an analogue voltage passes a threshold.
LFO - Low Frequency oscillator - just using a Schmitt Trigger you can not make a LFO, you need other components and some feedback circuit.
ported - the act of converting code for one machine to another.
to teensys input - assuming that you mean teensy's input and not the input of many teensies -  as a teensey is by and large compatible with the Arduino I am not sure what you have ported.

So all this means sure you vcan get help here but give us a chance. Why not read the rules:- How to use this forum

harish017

Ok, nevermind if it doesn't make sense. Offcourse, I am using other components along with Schmitt Trigger and yes with a feedback loop.

Let me put this more clear of what I am going to accomplish.

"I will be using an analog signal such as an audio triggered from an external circuit to vary digital values such as tone pitch programmed in teensy"

External audio signals will be from LFO with waveforms like sine, saw, square and so on.


Paul Stoffregen

It still makes no sense, at least to me.

Without "Schmitt Trigger" and "feedback loop", this could perhaps involve analogRead() to measure the low frequency signal, and then use the result to control tone() or DDS-based waveforms such as AudioSynthWaveform in the Teensy Audio Library.

But somehow a schmitt trigger device is involved.  Do you understand we can not see your workbench?  Can you imagine how other people read your message without any idea which particular chip you're using, or how it's connected, or even *why* you want a schmitt trigger rather than simply reading the analog voltage?

Likewise, what does a feedback loop have to do with any of this?  Again, I am curious no such much about what you are actually doing, but I want to understand how you believe writing these messages without details is a good idea?  You're spending your own time to write these messages, and consuming the time of people like us who read them and might really try to help you, but instead we consume precious time with mystery and unknowns about what you're trying to say.

Really, it's personal goal of mine to improve forum support for everyone, everywhere, in the entire Arduino community.  Yes, a huge and perhaps impossible goal.  But if you will help me for even just a minute, I want to understand *why* you write these messages?  I want to know your thought process.  I want to eventually find ways to improve forums so novices will intuitively understand how to write good questions, and so I really want to understand how you think.

harish017

The reason why I posted here is, I didn't find my answer using google search. Anyhow, I have my vision clear and I am sure I will do it. What do you mean workbench? This is my flow LFO(using Schmitt Trigger and 7555 timer)-->Teensy(Oscillator,filter and few fx)-->LM386-->Audio Output. Thanks for the functions, will work on it. Should I post my schematics? To have a clear understanding what I am doing?

Grumpy_Mike

Quote
I have my vision clear and I am sure I will do it.
Once that vision is communicated then we can help. Paul and I are probably the most experienced with audio on this site. Paul has written some great DSP drivers on his (he designs and builds them)  Teensey systems and I have written a book on Arduino audio.

Quote
Should I post my schematics?
Yes please.

Quote
The reason why I posted here is, I didn't find my answer using google search.
Searching requires you use the same words as the rest of the world. This could be your problem.

harish017

Here, still working on it. I am looking forward to send control signals so that I can do the modulation.

Grumpy_Mike

The OUT pin of a 555 chip is digital, that is it will be either 0 or 1, so why are you feeding this into an analogue pin?
If you want to modulate something depending on the LFO then I would have thought you would have been better off taping the control voltage on the timer.

Paul Stoffregen

#8
Aug 06, 2016, 02:46 pm Last Edit: Aug 06, 2016, 02:49 pm by Paul Stoffregen
Why build this timer circuit?

Do you know you can implement LFOs with the audio library objects and use their outputs to modulate frequency or amplitude of other oscillators inside Teensy with the audio library?

I recommend watching the oscillators portion of the tutorial video.  That part starts at 25:04 in the video:

https://www.youtube.com/watch?v=wqt55OAabVs

This project would be much simpler hardware if you just connect the pot to an analog pin, of course with the sides to GND and 3.3V.  Then write a small piece of code in loop() using analogRead() to detect the pot position and change the oscillator settings.  Again, see the tutorial example which does this.  Click File > Examples > Audio > Tutorial > Part_2_08_Oscillators.

The audio library has an oscillator object with sawtooth, triangle, sine, square and pulse waveforms.  It can oscillate at low sub-audible frequencies, down to 0.01 Hz, and of course up to 22 kHz.  Very easy to control from the Arduino sketch.  The oscillator code inside the audio library uses DDS synthesis which uses the high quality crystal as its time-base, so the quality is excellent (better than those 555 timers).

Go Up
 


Please enter a valid email to subscribe

Confirm your email address

We need to confirm your email address.
To complete the subscription, please click the link in the email we just sent you.

Thank you for subscribing!

Arduino
via Egeo 16
Torino, 10131
Italy